Communication method using a carrier aggregation and apparatus therefore

ABSTRACT

The present invention is directed to a wireless communication system. More specifically, the present invention is directed to a method and an apparatus of controlling uplink transmission at a user equipment in a wireless communication system, wherein the user equipment is connected to multiple component carriers, which includes receiving configuration information for transmitting an uplink signal from a base station; and identifying a time for transmitting the uplink signal to the base station on a corresponding uplink component carrier in use of the configuration information, wherein if the corresponding uplink component carrier is in a non-available state at the time for transmitting the uplink signal, the uplink signal is not transmitted.

TECHNICAL FIELD

The present invention relates to a wireless (or radio) communicationsystem. And, more particularly, the present invention relates to acommunication method using a carrier aggregation and apparatustherefore.

BACKGROUND ART

Wireless communication systems are being broadly developed in order toprovide various types of communication services, such as voice or dataservices. Generally, a wireless communication system corresponds to amultiple access system that may support communication with multipleusers by sharing available system resources (bandwidth, transmissionpower, etc.). Examples of a multiple access system include a CDMA (codedivision multiple access) system, an FDMA (frequency division multipleaccess) system, a TDMA (time division multiple access) system, an OFDMA(orthogonal frequency division multiple access) system, an SC-FDMA(single carrier frequency division multiple access) system, an MC-FDMA(multi carrier frequency division multiple access) system, and so on.

DISCLOSURE OF INVENTION Technical Problem

An object of the present invention devised to solve the problem lies onproviding a method and apparatus for efficiently performingcommunication in a wireless communication system supporting carrieraggregation. Another object of the present invention devised to solvethe problem lies on providing a method and apparatus for efficientlycontrolling multiple component carriers. A further object of the presentinvention devised to solve the problem lies on providing a method forefficiently transmitting uplink signals and an apparatus for the same.

The technical objectives that are to be realized by the presentinvention will not be limited only to the technical objects pointed outherein. Other technical objectives that have not yet been mentionedherein will become apparent to those having ordinary skill in the artupon examination of the following or may be learned from practice of theinvention.

Solution to Problem

In an aspect of the present invention, a method of controlling uplinktransmission at a user equipment in a wireless communication system,wherein the user equipment is connected to multiple component carriersis provided, in which the method includes receiving configurationinformation for transmitting an uplink signal from a base station; andidentifying a time for transmitting the uplink signal to the basestation on a corresponding uplink component carrier in use of theconfiguration information, wherein if the corresponding uplink componentcarrier is in a non-available state at the time for transmitting theuplink signal, the uplink signal is not transmitted on the correspondingcomponent carrier.

In another aspect of the present invention, a user equipment configuredto communicate with a base station in a wireless communication system isprovided, in which the user equipment includes a radio frequency (RF)unit configured to transmit and receive wireless signals to and from thebase station by using multiple component carriers; a memory configuredto store information being transmitted and received to and from the basestation and parameters required for performing operations of the userequipment; and a processor configured to be connected to the RF unit andthe memory, and configured to control the RF unit and the memory, so asto operate the user equipment, and wherein the processor is configuredto receive configuration information for transmitting an uplink signalfrom the base station and to identify a time for transmitting the uplinksignal to the base station on a corresponding uplink component carrierin used of the configuration information, wherein if the correspondinguplink component carrier is in a non-available state at the time fortransmitting the uplink signal, the uplink signal is not transmitted onthe corresponding component carrier.

Herein, the configuration information may include information forperiodically transmitting the uplink signal to the base station. In thiscase, the uplink signal may include at least one of a CQI (ChannelQuality Indicator), a PMI (Precoding Matrix Indication), an RI (RankInformation), and an SRS (Sounding Reference Signal).

Herein, whether or not the corresponding uplink component carrier is ina non-available state may be identified by using a state of a downlinkcomponent carrier linked to the corresponding uplink component carrier.In this case, the corresponding uplink component carrier may beconfigured as a non-available state, when multiple downlink componentcarriers linked to the corresponding uplink component carrier are all ina non-available state. Furthermore, whether or not the correspondinguplink component carrier may be in a non-available state is identifiedby using L1/L2 control signaling.

In another aspect of the present invention, a method of transmitting anuplink signal from a user equipment to a base station in a wirelesscommunication system, wherein the user equipment is connected tomultiple component carriers, is provided. The method includes setting-upa first configuration for transmitting the uplink signal; identifying atime for transmitting the uplink signal in use of the firstconfiguration; and, when the time overlaps with a non-available durationof a carrier component related to the uplink signal, transmitting theuplink signal to the base station according to a second configuration,and wherein, in the second configuration, at least one of informationrelated to a transmission cycle period and information related to afrequency band is different from the first configuration.

In a further aspect of the present invention, a user equipmentconfigured to communicate with a base station in a wirelesscommunication system is provided, in which the user equipment includes aradio frequency (RF) unit configured to transmit and receive wirelesssignals to and from the base station by using multiple componentcarriers; a memory configured to store information being transmitted andreceived to and from the base station and parameters required forperforming operations of the user equipment; and a processor configuredto be connected to the RF unit and the memory, and configured to controlthe RF unit and the memory, so as to operate the user equipment, andwherein the processor is configured to set-up a first configuration fortransmitting the uplink signal, to identify a time for transmitting theuplink signal in use of the first configuration, and to transmit theuplink signal to the base station according to a second configurationwhen the time overlaps with a non-available duration of a carriercomponent related to the uplink signal, and wherein, in the secondconfiguration, at least one of information related to a transmissioncycle period and information related to a frequency band is differentfrom the first configuration.

Advantageous Effects of Invention

According to the embodiments of the present invention, communication maybe efficiently performed in a wireless communication system supportingcarrier aggregation. Also, multiple component carriers may beefficiently controlled. Additionally, an uplink signal may beefficiently transmitted by using multiple component carriers. Morespecifically, when the states of the multiple component carriers arechanged (or shifted) dynamically, a CQI or SRS may be efficientlytransmitted. Furthermore, in an asymmetric carrier aggregationenvironment (or condition), the state of the component carriers may beefficiently configured (or set-up).

The effects that can be achieved in the present invention will not belimited only to the effects pointed out in the description of thepresent invention. Other effects that have not yet been mentioned hereinwill become apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a network structure of an E-UTMS (Evolved UniversalMobile Telecommunications System).

FIG. 2 illustrates an exemplary radio (or wireless) interface protocolstructure between a user equipment and an E-UTRAN based upon a 3GPPradio access network standard.

FIG. 3 illustrates an exemplary structure of a radio frame used in anLTE.

FIG. 4 illustrates an example of performing communication in a singlecomponent carrier condition.

FIG. 5 illustrates an exemplary structure of an uplink subframe used inthe LTE.

FIG. 6 to FIG. 8 illustrate examples of periodically transmitting uplinksignals.

FIG. 9 illustrates an example of performing communication under amultiple component carrier condition.

FIG. 10 illustrates an example of setting up a component carriercondition according to an embodiment of the present invention.

FIG. 11 to FIG. 17 illustrate examples of transmitting uplink signalsaccording to an embodiment of the present invention.

FIG. 18 illustrates examples of a base station and a user equipment thatcan be applied to an embodiment of the present invention.

MODE FOR THE INVENTION

The structure, application, and other characteristics of the presentinvention may be understood by the foregoing general description and thefollowing detailed description of the embodiments of the presentinvention with reference to the following drawings. Herein, theembodiments of the present invention may be applied in diverse wireless(or radio) access technologies, such as CDMA, FDMA, TDMA, OFDMA,SC-FDMA, and MC-FDMA. The CDMA may be embodied with wireless technologysuch as UTRA (Universal Terrestrial Radio Access) or CDMA2000. The TDMAmay be embodied with wireless technology such as GSM (Global System forMobile communications)/GPRS (General Packet Radio Service)/EDGE(Enhanced Data Rates for GSM Evolution). The OFDMA may be embodied withwireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),IEEE 802.20, and E-UTRA (Evolved UTRA). The UTRA is a part of the UMTS(Universal Mobile Telecommunications System). The 3GPP (3rd GenerationPartnership Project) LTE (long term evolution) is a part of the E-UMTS(Evolved UMTS), which uses E-UTRA. The LTE-A (Advanced) is an evolvedversion of the 3GPP LTE.

The following embodiments of the present invention mainly describeexamples of the technical characteristics of the present invention beingapplied to the 3GPP system. However, this is merely exemplary.Therefore, the present invention will not be limited only to theembodiments of the present invention described herein.

FIG. 1 is a diagram illustrating a network structure of an EvolvedUniversal Mobile Telecommunications System (E-UMTS). The E-UMTS may alsobe referred to as a Long Term Evolution (LTE) system. For details of thetechnical specifications of the UMTS and the E-UMTS, refer to Release 7and Release 8 of “3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network”.

Referring to FIG. 1, the E-UMTS includes a User Equipment (UE) (120),base stations (eNode B or eNB) (110 a and 110 b), and an Access Gateway(AG) which is located at an end of a network (E-UTRAN) and connected toan external network. The base stations can simultaneously transmitmultiple data streams for a broadcast service, a multicast serviceand/or a unicast service. One or more cells may exist for one basestation. One cell is set to one of bandwidths of 1.25, 2.5, 5, 10, and20 Mhz. Different cells may be set to provide different bandwidths.Also, one base station controls data transmission and reception for aplurality of user equipments. The base station transmits downlink (DL)scheduling information of downlink data to the corresponding userequipment to notify information related to time and frequency regions towhich data will be transmitted, encoding, data size, and HARQ (HybridAutomatic Repeat and reQuest). Also, the base station transmits uplink(UL) scheduling information of uplink data to the corresponding userequipment to notify information related to time and frequency domainsthat can be used by the corresponding user equipment, encoding, datasize, and HARQ. An interface for transmitting user traffic or controltraffic can be used between the base stations. A Core Network (CN) mayinclude the AG and a network node or the like for user registration ofthe UE. The AG manages mobility of a UE on a TA (Tracking Area) basis,wherein one TA includes a plurality of cells.

FIG. 2 is a diagram illustrating structures of a control plane and auser plane of a radio interface protocol between a user equipment andE-UTRAN based on the 3GPP radio access network standard. The controlplane means a passageway where control messages are transmitted, whereinthe control messages are used in the user equipment and the network tomanage call. The user plane means a passageway where data generated inan application layer, for example, voice data or Internet packet data,are transmitted.

A physical layer as a first layer provides an information transferservice to an upper layer using a physical channel. The physical layeris connected to a medium access control layer above the physical layervia a transport channel. Data are transferred between the medium accesscontrol layer and the physical layer via the transport channel. Data aretransferred between one physical layer of a transmitting side and theother physical layer of a receiving side via the physical channel. Thephysical channel uses time and frequency as radio resources.Specifically, the physical channel is modulated in accordance with anOFDMA (Orthogonal Frequency Division Multiple Access) scheme in adownlink, and is modulated in accordance with a SC-FDMA (Single CarrierFrequency Division Multiple Access) scheme in an uplink.

A medium access control layer of a second layer provides a service to aradio link control (RLC) layer above the MAC layer via a logicalchannel. The RLC layer of the second layer supports reliable datatransfer. The RLC layer may be implemented as a functional block insidethe MAC layer. In order to effectively transmit IP packets such as IPv4or IPv6 within a radio interface having a narrow bandwidth, a packetdata convergence protocol (PDCP) layer of the second layer performsheader compression to reduce the size of unnecessary controlinformation.

A radio resource control (RRC) layer located on a lowest part of a thirdlayer is defined in the control plane only. The RRC layer is associatedwith configuration, reconfiguration and release of radio bearers (RBs)to be in charge of controlling the logical, transport and physicalchannels. In this case, the RB means a service provided by the secondlayer for the data transfer between the user equipment and the network.To this end, the RRC layers of the user equipment and the networkexchange RRC messages with each other. If the RRC layer of the userequipment is RRC connected with the RRC layer of the network, the userequipment is in RRC connected mode. If not so, the user equipment is inRRC idle mode. A NAS (Non-Access Stratum) layer located above the RRClayer performs functions such as session management and mobilitymanagement.

As downlink transport channels carrying data from the network to theuser equipment, there are provided a BCH (Broadcast Channel) carryingsystem information, a PCH (Paging Channel) carrying paging message, anda downlink SCH (Shared Channel) carrying user traffic or controlmessages. Traffic or control messages of a downlink multicast orbroadcast service may be transmitted via the downlink SCH or anadditional downlink MCH (Multicast Channel). Meanwhile, as uplinktransport channels carrying data from the user equipment to the network,there are provided a RACH (Random Access Channel) carrying an initialcontrol message and an uplink SCH (Shared Channel) carrying user trafficor control message. As logical channels located above the transportchannels and mapped with the transport channels, there are provided aBCCH (Broadcast Control Channel), a PCCH (Paging Control Channel), aCCCH (Common Control Channel), a MCCH (Multicast Control Channel), and aMTCH (Multicast Traffic Channel).

FIG. 3 is a diagram illustrating a structure of a radio frame used inthe LTE system.

Referring to FIG. 3, the radio frame has a length of 10 ms (327200×Ts)and includes 10 subframes of an equal size. Each subframe has a lengthof 1 ms and includes two slots. Each slot has a length of 0.5 ms(15360×Ts). In this case, Ts represents a sampling time, and isexpressed by T_(s)=1/(15 kHz×2048)=3.2552×10⁻⁸ (about 33 ns). The slotincludes a plurality of OFDM symbols in a time domain, and includes aplurality of resource blocks (RBs) in a frequency domain. In the LTEsystem, one resource block includes twelve (12) subcarriers×seven (orsix) OFDM symbols. A Transmission Time Interval (TTI) which is atransmission unit time of data can be determined in a unit of one ormore subframes. The aforementioned structure of the radio frame is onlyexemplary, and various modifications can be made in the number ofsubframes included in the radio frame or the number of slots included inthe subframe, or the number of OFDM symbols included in the slot.

FIG. 4 illustrates an example of a communication process being performedin a single component carrier wave condition. FIG. 4 may correspond toan example of a communication process in an LTE system.

Referring to FIG. 4, a general FDD-type wireless communication systemperforms signal (e.g., data, control information) transmission and/orreception through one downlink band and one uplink band corresponding tothe downlink band. The base station and user equipment transmits and/orreceives data and/or control information scheduled in subframe units.Herein, the data are transmitted and/or received through a data regiondetermined in the up-/downlink subframe, and the control information istransmitted and/or received through a control region determined in theup-/downlink subframe. For this, the up-/downlink subframe deliverssignals through a plurality of physical channels. FIG. 4 mainlydescribes the FDD mode for simplicity. However, the above-describeddetail may also be applied in the TDD mode, by differentiating thewireless (or radio) of FIG. 3 into up-/downlink portions in the timedomain.

In a downlink, the control region starts from a first OFDMA symbol of asubframe and includes at least one or more OFDMA symbols. The size ofthe control region may be independently configured (or determined) foreach subframe. The control region is used for transmitting L1/L2 (layer1/layer 2) control signals. The data region is used for transmittingdownlink traffic. Control channels being assigned to the control regioninclude PCFICH (Physical Control Format Indicator CHannel), PHICH(Physical Hybrid-ARQ Indicator CHannel), and PDCCH (Physical DownlinkControl CHannel).

The PDCCH is assigned to the first n number of OFDM symbols of asubframe. Herein, n is an integer more than or equal to 1, which isindicated by PCFICH. The PDCCH is configured of one or more CCEs. EachCCE includes 9 REGs, and each REG consists of 4 resource elementsadjacent to one another while excluding a reference signal. A resourceelement corresponds to a minimum resource unit defined as 1 subcarrier×1symbol. The PDCCH notifies information on resource assignment (orallocation) of transmitting channels PCH (Paging channel) and DL-SCH(Downlink-shared channel), Uplink Scheduling Grant, HARQ information,and so on to each user equipment (or user terminal) or user equipmentgroup. The PCH (Paging channel) and the DL-SCH (Downlink-shared channel)are transmitted through the PDSCH. Information on which user equipment(one or a plurality of user equipments) data of the PDSCH are to betransmitted, and information on how the user equipments are to receiveand decode the PDSCH data are included in the PDCCH, thereby beingtransmitted. For example, it is assumed that a specific PDCCH is CRCmasked with an RNTI (Radio Network Temporary Identity) “A”, and thatinformation on the data being transmitted by using a radio (or wireless)resource (e.g., frequency position) “B” and a transmission formatinformation (e.g., transmission block size, modulation method, codinginformation, and so on) “C” is transmitted through a specific subframe.A user equipment of the corresponding cell uses its own RNTI informationto monitor the PDCCH, and a user equipment having the RNTI “A” receivesthe PDCCH. Then, by using the information on the received PDCCH, thePDSCH indicated by “B” and “C” is received.

FIG. 5 illustrates an exemplary structure of an uplink subframe used inthe LTE.

Referring to FIG. 5, a subframe (500) having the length of 1 ms, whichis a basic unit for uplink transmission, is configured of two 0.5 msslots (501). When the length of a normal Cyclic Prefix (CP) is assumedto be used, each slot is configured of 7 symbols (502), and each symbolcorresponds to one SC-FDMA symbol. A Resource Block (RB) (503) is aresource assignment (or allocation) unit corresponding to 12 carriers inthe frequency region and one slot in the time region. The uplinksubframe is divided into a data region (504) and a control region (505).

The data regions includes an uplink shared channel (PUSCH) and is usedfor transmitting data signals, such as voice (or sound), image, and soon. The control region includes an uplink control channel (PUCCH) and isused for transmitting control information. The PUCCH includes an RB pairlocated at each end of the data region in a frequency axis and hops at aslot boundary. The control information includes HARQ ACK/NACK andchannel information on the downlink (hereinafter referred to as downlinkchannel information or channel information). The downlink channelinformation includes CQI (Channel Quality Indicator), PMI (PrecodingMatrix Indication), RI (Rank information), and so on. The base stationuses the downlink channel information received from each user equipment,so as to decide time/frequency source, modulation methods, coding rates,and so on appropriate for transmitting data to each user equipment.

In the LTE system, depending upon the channel information transmissionmode, each user equipment may transmit all or only a portion of the CQI,PMI, RI, and so on. A case where the channel information is periodicallytransmitted is referred to as periodic reporting, and a case where thechannel information is transmitted only upon request from the basestation is referred to as aperiodic reporting. In case of the aperiodicreporting, a request bit, which is included in the uplink schedulinginformation sent from the base station, is transmitted to the userequipment. Thereafter, the user equipment delivers channel information,wherein its own transmission mode is taken into consideration, to thebase station through an uplink data channel (PUSCH). In case of theperiodic reporting, a cycle period and an offset in the correspondingcycle period are signaled in subframe units to each user equipment in asemi-static manner through an upper layer signaling. Each user equipmentdelivers channel information considering its respective transmissionmode to the base station through the uplink control channel (PUCCH)based upon a pre-decided cycle period. If uplink data coexist in thesubframe transmitting the channel information, the channel informationis transmitted through the uplink data channel (PUSCH) along with thedata. The base station transmits transmission timing informationappropriate for each user equipment, while taking into consideration thechannel condition of each user equipment and a user equipment dispersion(or distribution) status within a cell. The transmission timinginformation includes a cycle period for transmitting channelinformation, and an offset. And, the transmission timing information maybe delivered to each user equipment through an RRC message.

Meanwhile, the user equipment (or terminal) transmits a SoundingReference Signal (SRS) in order to notify the base station of uplinkchannel information. In the LTE, the SRS is transmitted through aduration including an SC-FDMA symbol, which is located at the very endof an uplink subframe in the time axis, and through a data transmissionband in the frequency axis. The SRS of multiple user equipments beingtransmitted to the last SC-FMDA of the same uplink subframe may bedifferentiated by the frequency position/sequence. For each userequipment, a cycle period for transmitting an SRS and an offset of thecorresponding cycle period may be signaled in subframe units through anupper-layer signaling in a semi-static manner. Depending upon itsconfigurations (or settings), the SRS may be transmitted through anentire band or a subband. And, in case the SRS is transmitted through asubband, a frequency band hopping may be performed when transmitting theSRS.

Configuration information (e.g., cycle period, offset, transmissionband, whether or not hopping is performed, etc.) for transmitting thechannel information on the downlink or the SRS may be assigned to theuser equipment from the base station via Cell-specific and/orUE-specific RRC signaling.

FIG. 6 to FIG. 8 illustrate examples of periodic reporting of channelinformation. Although the following drawings are mostly based upon thecase of transmitting downlink channel information (e.g., CQI, PMI, RI,etc.) for simplicity, the examples may also be applied to the case oftransmitting uplink channel information (e.g., SRS, etc.).

FIG. 6 illustrates an example of transmitting channel information whenthe user equipment is signaled with an information indicating {period‘5’, offset ‘1’}. Referring to FIG. 6, when receiving informationindicating that the cycle period is ‘5’ and that the offset is ‘1’, theuser equipment transmits channel information in five (5) subframe unitsstarting from a 0th subframe in an increasing direction of the subframeindex with the offset of one (1) subframe. The channel information isessentially transmitted through the PUCCH. However, if a PUSCH exists,wherein the PUSCH is used for transmitting data at the same time as thePUCCH, the channel information is transmitted through the PUSCH alongwith the data. The subframe index is configured of a combination of asystem frame number (nf) and a slot index (n_(s), 0˜19). Since thesubframe consists of two (2) slots, the subframe index may be defined as10×n_(f)+floor(n_(s)/2). Herein, the floor( ) indicates a floorfunction.

FIG. 7 illustrates an example of a system having a system bandconfigured of sixteen (16) RBs. In this case, it is assumed that thesystem band consists of two (2) BPs (Bandwidth Parts), that each BP isconfigured of two (2) SBs (subbands) (SB0, SB1), and that each SBconsists of four (4) RBs. The above-mentioned assumption is merelyexemplary, and, therefore, depending upon the size of the system band,the number of BPs and the size of the SBs may vary. Also, depending uponthe number of RBs, the number of BPs, and the size of the SBs, thenumber of SBs configuring each BP may also vary. In case of the typetransmitting both WB CQI and SB CQI, the WB CQI and the SB CQI arealternately transmitted. Meanwhile, in case of the type transmittingalso the PMI depending upon the PMI feedback type, the PMI informationis transmitted along with the CQI information.

FIG. 8 illustrates an example of transmitting both WB CQI and SB CQIwhen the user equipment is signaled with an information indicating{period ‘5’, offset ‘1’}. Referring to FIG. 8, regardless of its type,the CQI may only be transmitted in a subframe corresponding to thesignaled cycle period and offset. FIG. 8( a) illustrates an examplewherein only the CQI is transmitted, and FIG. 8( b) illustrates anexample wherein the CQI is transmitted along with the RI. The RI, whichconsists of a combination of the multiple of WB CQI transmission cycleperiod by which the RI is being transmitted and an offset of thecorresponding cycle period, may be signaled from an upper layer (e.g.,RRC layer). For example, if the CQI offset is ‘1’, and if the RI offsetis ‘0’, the RI has the same offset as the CQI. The offset value of theRI is defined as 0 and a negative number. More specifically, it isassumed that in FIG. 8( b), in an environment identical to that of FIG.8( a), the RI transmission cycle period is a one (1) time multiple ofthe WB CQI transmission cycle period, and that the RI offset is ‘−1’. Incase the transmission subframe of the WB CQI and the RI overlap, the WBCQI is dropped, and the RI is transmitted.

FIG. 9 illustrates an example of performing communication under amultiple component carrier situation. Herein, in order to use a broader(or wider) frequency band, the LTE-A system uses a carrier aggregation(or bandwidth aggregation) technology, which gathers multipleup-/downlink frequency blocks so as to use a larger up-/downlinkbandwidth. Each frequency block is transmitted by using a componentcarrier (CC). In the description of the present invention, dependingupon the context, the component carrier (CC) may refer to a frequencyblock for carrier aggregation or a center carrier of the frequencyblock, and such definitions may be alternately used herein.

Referring to FIG. 9, five (5) 20 MHz CCs may be gathered in each of theuplink and downlink, so as to support a 100 MHz bandwidth. Each of theCCs may be adjacent or non-adjacent to one another in the frequencydomain. For simplicity, FIG. 9 illustrates a case where the bandwidth ofan uplink component carrier and the bandwidth of a downlink componentcarrier are both identical and symmetrical to one another. However, thebandwidth of each component carrier may be independently decided. Forexample, the bandwidth of the uplink component carrier may be configuredas 5 MHz (UL CC0)+20 MHz (UL CC1)+20 MHz (UL CC2)+20 MHz (UL CC3)+5 MHz(UL CC4). Also, an asymmetrical carrier aggregation, wherein the numberof uplink component carriers and the number of downlink componentcarriers are different from one another, may also be performed. Theasymmetrical carrier aggregation may be caused by a limit in availablefrequency bands or artificially created by network settings. Forexample, even if the overall system band is configured of N number ofCCs, the frequency band that can be received by one specific userequipment may be limited to M(<N) number of CCs. Hereinafter, theembodiments of the present invention are mostly described with respectto the case where N number of CCs is applied, for simplicity. However,it is also apparent that the embodiments may be applied to a case whereM number of CCs is applied. Furthermore, the N (or M) number of CCsassigned to the user equipment is divided into L number of CC groups,and the embodiments of the present invention may also be applied to eachCC group.

Embodiment 1 Status Configurations (or Settings) of a Component Carrier

When the user equipment accesses (or is connected to) a cell configuredof multiple DL CCs, in order to reduce battery power consumption of theuser equipment, the base station limits a general (or normal)control/data reception to only one DL CC or some DL CCs among the totalDL CCs of the system. As for the remaining DL CCs, the base station mayassign (or allocate) DL CCs so that the reception can be limited. Forsimplicity, DL CC(s) assigned (or allocated) so that the general (ornormal) control/data reception can be performed with respect to acertain user equipment is/are defined as active DL CC(s). And, theremaining DL CC(s) is/are defined as non-active DL CC(s). For example, abase station controlling a cell configured of 5 DL CCs, as shown in FIG.9, may assign only one DL CC to a certain user equipment as the activeDL CC and may assign the remaining 4 DL CCs as the non-active DL CCs.Herein, the active/non-active DL CCs may be assigned semi-statically ordynamically. And, in order to do so, RRC signaling, L1/L2 controlsignaling (e.g., PDCCH), or a separately defined signaling may be used.The active/non-active DL CCs may be assigned by using a channelcondition (or status), required amount of downlink traffic, downlinktraffic, or any combination of the above. In the description of thepresent invention, unless the active/non-active DL CCs are specificallydifferentiated by definition and described accordingly,active/non-active DL CCs may be used along with its equivalent terms,such as available/non-available DL CCs or activated/deactivated DL CCs.

As shown in FIG. 9, when multiple DL CCs and UL CCs exist, the basestation may configure (or set-up) a semi-static or dynamic linkagebetween a specific UL CC and a specific DL CC, so as to signal the userequipment. The linkage relation between the DL CC and the UL CC may beconfigured (or set-up) by Cell-specific or UE-specific RRC signaling orL1/L2 control signaling (e.g., PDCCH). In this case, in order to performreduction in signaling overhead, the present invention proposes a methodof automatically configuring (or setting-up) the state of the UL CC insynchronization with the state of the DL CC linked with the UL CC. Morespecifically, when a specific DL CC is assigned as an active DL CC, theUL CC linked with the corresponding DL CC is automatically configured tobe able to perform transmission of an uplink signal. For simplicity,such UL CC may be referred to as an available UL CC, and it can be saidthat the corresponding UL CC is in an available state. Conversely, whena specific DL CC is assigned as a non-active DL CC, the UL CC linked tothe corresponding DL CC is automatically configured not to performtransmission of all or some uplink signals. For simplicity, such UL CCmay be referred to as a non-available UL CC, and it can be said that thecorresponding UL CC is in a non-available state. In the description ofthe present invention, unless the available/non-available UL CCs arespecifically differentiated by definition and described accordingly,available/non-available UL CCs may be used along with its equivalentterms, such as active/non-active UL CCs or activated/deactivated UL CCs.

Since the DL CC may be semi-statically or dynamically configured (orset-up) as and changed as active/non-active DL CCs, the UL CC linked tothe corresponding DL CC is also automatically semi-statically ordynamically configured as an available/non-available UL CC. In otherwords, the UL CC may be semi-statically or dynamically shifted to anavailable/non-available state depending upon the state of the DL CCwithin the time axis. At this point, the available/non-available UL CCconfigurations (or settings) of the UL CC in accordance with theactive/non-active DL CC assignment of the DL CC may not necessarilyexist at the same timing, and, accordingly, there may exist apredetermined timing interval.

FIG. 10 illustrates an example of configuring (or setting) a UL CC statedepending upon a mapping (i.e., linkage) relation between the UL CC andthe DL CC. Case 1 shows an example wherein the DL CC and the UL CC aremapped in a one-to-one (one DL CC to one UL CC) correspondence. Case 2shows as example wherein the DL CC and the UL CC are mapped in amultiple-to-one (multiple DL CCs to one UL CC) correspondence. And, Case3 shows an example wherein the DL CC and the UL CC are mapped in aone-to-multiple (one DL CC to multiple UL CCs) correspondence. Theasymmetrical mapping examples, such as Case 2 and Case 3, may occur inan asymmetrical carrier aggregation environment.

Referring to Case 1, when a linked DL CC is assigned as an active DL CC,the UL CC is automatically configured (or set-up) as an available UL CC,and when a linked DL CC is assigned as a non-active DL CC, the UL CC isautomatically configured (or set-up) as a non-available UL CC. Referringto Case 2, among the DL CCs linked to the UL CC, even when only one DLCC is assigned as an active DL CC, the UL CC may be automaticallyconfigured as an available UL CC. Meanwhile, only when all DL CCs linkedto the UL CC are assigned as non-active DL CCs, the corresponding UL CCmay be configured as a non-available UL CC. Referring to Case 3, whenone DL CC is assigned as an active DL CC, all linked UL CCs areconfigured as available UL CCs. And, when the corresponding DL CC isassigned as a non-active DL CC, then all linked UL CCs may be configuredas non-available UL CCs.

Embodiment 2 Control of Uplink Transmission in a Carrier AggregationCondition

In a conventional 3GPP system, the uplink transmission time of some ofthe uplink signals is decided based upon a predeterminedconfiguration/timing. For example, when receiving downlink data, anACK/NACK signal respective to the downlink data is automaticallytransmitted after a predetermined time has elapsed from the downlinkdata reception point. Also, the user equipment periodically reportschannel information on downlink (e.g., CQI, PMI, RI, etc.) to the basestation, and the user equipment also periodically transmits uplinksignals (e.g., SRS) so that the base station can measure the channelstatus of the uplink. In order to facilitate the understanding of thepresent invention, hereinafter description will be made by using uplinksignals associated with the downlink, or preferably, by using CQI as amain example of downlink channel information, and by using SRS a mainexample of a signal associated with uplink. Configuration informationfor transmitting CQI, SRS, and so on (e.g., cycle period, offset,transmission band, whether or not hopping is performed, etc.) may besignaled via Cell-specific and/or UE-specific RRC signaling.

When a cell is configured of multiple UL CCs, the user equipment shouldtransmit SRS for uplink channel status measurement of the multiple ULCCs to the base station, and the user equipment should also transmit CQIinformation for each DL CC. In case of the CQI (or SRS), a transmissioncycle is given by RRC signaling, and once such signaling is performed,transmission should be performed in accordance with the signaledtransmission cycle during a predetermined period (e.g., until thesettings are changed or cancelled). Meanwhile, in a carrier aggregationcondition, a DL CC may be statically or semi-statically assigned as anactive/non-active DL CC, and, a UL CC may be automatically configured asan available/non-available UL CC depending upon a state of a linked DLCC as explained in Embodiment 1. Unlike the Embodiment 1, a UL CC may beindependently configured as an available/non-available UL CC, by usingRRC signaling, L1/L2 control signaling (e.g., PDCCH), or a separatelydefined signaling, without relying on the state of a DL CC linked to theUL CC.

Therefore, when the corresponding DL/UL CC is configured to be in anon-active (non-available) state at the time when an uplink signal(e.g., CQI, SRS, etc.) is to be transmitted in accordance with theconfiguration information, since the operation for transmitting theuplink signal and the operation according to the definition of thenon-active (non-available) DL/UL may be the opposite of one another, amethod for resolving such problem is required. For example, when thecorresponding UL CC is configured to be in a non-available state at aCQI (or SRS) transmission time, a method of giving priority to the CQI(or SRS) transmission and configuring the non-available UL CC to anavailable UL CC in accordance with the CQI (or SRS) transmission cyclemay be considered. However, in order to configure the corresponding ULCC as an available UL CC, the DL CC linked to the corresponding UL CCshould be assigned as an active DL CC. Therefore, a reduction in batterypower consumption through non-active DL CC configurations cannot belargely obtained.

Accordingly, when the corresponding DL/UL CC is in a non-active(non-available) state at the time when uplink signal should betransmitted in accordance the configuration information, the presentinvention proposes to change the configuration (e.g., transmissiontime/pattern/band) for transmitting uplink signals so as to performlimited transmission, or not to transmit uplink signals.

FIG. 11 shows an example of the user equipment controlling the uplinksignal transmission in a carrier aggregation condition according to anembodiment of the present invention. Referring to FIG. 11, in order totransmit an uplink signal, the user equipment may (semi-statically)receive a parameter for deciding/identifying an uplink physical channel(signal) assignment from the base station (S1110, option). The uplinksignal includes a signal, e.g., CQI, PMI, RI, SRS, etc., beingperiodically transmitted. The parameter being received from the basestation includes cycle period information, offset information, band, andso on, for transmitting the uplink signal. Thereafter, the userequipment performs a procedure for deciding/identifying the uplinkphysical channel (signal) assignment (S1120). Through this procedure, aUL CC index, an uplink transmission time (e.g., UL subframe index), andso on for transmitting the uplink physical channel (signal) may bedecided.

Thereafter, in case the uplink physical channel (signal) is to betransmitted via the non-available duration (or portion) of the UL CC(e.g., subframe, slot, OFDM or SC-FDMA symbol), the user equipment maynot transmit the uplink physical channel (signal) (S1130, option (a)).More specifically, a user equipment, which is assigned with atransmission cycle period of the CQI (or SRS) for each CC via RRCsignaling, transmits the CQI (or SRS), only when the transmission cycleperiod of the CQI (or SRS) matches the time when the corresponding UL CCis configured as an available UL CC. And, even though the cycle periodcorrespond to the cycle period of the CQI (or SRS), when thecorresponding UL CC failed to be assigned as an available UL CC, i.e.,when the corresponding UL CC is assigned as a non-available UL CC, theuser equipment does not transmit the CQI (or SRS). In another method,the user equipment may transmit the uplink physical channel (signal) byusing a method other than the initial configuration (parameter) (e.g.,changing the cycle period, changing the pattern) (S1130, option (b)). Adetailed description will be given on option (a) and option (b) and adetailed description on the varied methods depending upon each conditionwill also be given with reference to FIGS. 12-15 and FIGS. 16-17,respectively.

Embodiment 2-1 Control of an Uplink Transmission Considering the Stateof the UL CC

FIG. 12 shows an example of controlling the uplink transmission inconsideration of the state of the UL CC. It is assumed in FIG. 12 that acell is configured of 3 CCs. In the drawing, although the CC may beinterpreted as DL CC or UL CC, in the following description, the CC isassumed to be a UL CC. In this embodiment of the present invention, withrespect to a user equipment, in case of CC#1, the UL CC is alwaysconfigured as an available UL CC. And, in case of CC#0 and CC#2, it isassumed that the UL CC is dynamically configured as anavailable/non-available UL CC depending upon the channel state and celltraffic load condition. Herein, it is assumed that 5, 3, and 4 subframesare respectively assigned as the transmission cycle period of the CQI(or SRS) for CC#1, CC#2, and CC#3.

Referring to FIG. 12, since CC#1 is always configured as the availableUL CC, in CC#1, the CQI (or SRS) is always transmitted for each set of 3subframes in accordance with the predetermined transmission cycleperiod. Conversely, since CC#0 and CC#2 are dynamically configured asavailable/non-available UL CCs, the CQI (or SRS) is transmitted onlywhen the corresponding CC# at a reserved transmission time (e.g.,subframe) is assigned as an available UL CC in accordance with thetransmission cycle period. And, in other case, the CQI (or SRS) is nottransmitted. In particular, a user equipment performs of determiningphysical uplink channel assignment for a transmission of the CQI (orSRS) at a subframe on which the CQI (or SRS) shall be transmitted, inwhich the CQI (or SRS) is configured not to be transmitted when acorresponding UL CC is in a state of non-available UL CC. That is, whenthe corresponding UL CC in a state of non-available UL CC, the userequipment may not assign a physical channel to the CQI (or SRS) at thecorresponding subframe. The procedure of determining physical channelassignment includes assigning uplink signals (e.g., the CQI (or SRS)) toa PUSCH or a PUCCH. FIG. 12 merely corresponds to one of the manyexamples for describing the present invention. And, this example may beapplied to the present invention regardless of the number of CCs,reporting cycle period, and so on. Also, the present invention may alsobe applied in cases for transmitting periodic or aperiodic signals otherthan the CQI (or SRS).

Meanwhile, when a specific CC is continuously configured as thenon-available UL CC, the CQI or SRS for the corresponding CC is alsocontinuously unavailable for transmission. However, in light of the basestation, the channel information reception and channel condition for thecorresponding CC are required to be measured. Therefore, in this case, amethod wherein the base station assigns the DL CC linked to thecorresponding UL CC as an active DL CC, so that the corresponding CC canbe configured as an available UL CC in the CQI and SRS transmissioncycle period, may be used. Also, an additional signaling may be defined,wherein the additional signaling does not assign a DL CC linked to thecorresponding UL CC as an active DL CC, and wherein the additionalsignaling configures the corresponding UL CC as an available CC only atthat specific time. In this case, the additional signaling for the UL CCmay be performed through a specific DL CC (e.g., anchor or primary DLCC), which is always being maintained in an active state in order totransmit the downlink control information.

Meanwhile, since the CQI corresponds to information indicating thechannel state of the DL CC, the CQI is not required to be alwaystransmitted through each UL CC. Accordingly, in FIG. 12, the CQItransmission, which is shown to be respectively transmitted throughCC#1˜CC#3, may be performed through one specific UL CC (e.g., anchor orprimary UL CC). In addition, as shown in FIG. 12, when the CQI (or SRS)is transmitted through multiple UL CCs, also available herein is amethod of transmitting the CQI (or SRS) using a TDM (Time DivisionMultiplexing) method between UL CCs by adjusting the transmission cycleperiod/offset between the UL CCs.

Embodiment 2-2 Control of an Uplink Transmission Considering the Stateof the DL CC (1)

When transmitting uplink information related to the DL CC, or,preferably, when transmitting downlink channel information (e.g., CQI)for the DL CC, there may be a situation wherein a linkage relationbetween the DL CC and the UL CC is not particularly configured. In thiscase, there may exist a plurality of methods for transmitting the UL CCthrough a CQI depending upon configurations, such as a CQI transmissionscheme and transmission cycle period. For example, CQI information formultiple DL CCs may be transmitted through one UL CC (e.g., anchor orprimary UL CC). In another example, when the CQI for multiple DL CCs istransmitted through multiple UL CCs, multiple CQI may be transmitted ina TDM (Time Division Multiplexing) method by adjusting the transmissioncycle period between the UL CCs. When the cycle period is the same,multiple CQIs may be simultaneously transmitted through multiple UL CC.Additionally, CQI transmission may be performed by using many othermethods. Only one transmission method may be used but, in some cases, aplurality of transmission methods may also be used.

Therefore, the present invention proposes a method of deciding thetransmission or non-transmission of the CQI depending upon theactive/non-active CC assignment of the DL CC, regardless of the CQItransmission method. More specifically, a CQI transmission cycle period,a timing offset, a UL CC that is to be transmitted, etc. are configuredin advance for all of the assigned DL CCs, and when the CQI that is tobe transmitted is associated with the active CC, the CQI is transmitted.And, when the CQI that is to be transmitted is associated with thenon-active CC, the CQI is not transmitted. In this case, the exemplarycondition given in S1130 of FIG. 11 may be changed to “if the uplinkphysical channel (signal) that is to be transmitted at the correspondingtime is related to the non-active duration (or portion) of the DL CC.”

FIGS. 13˜15 show examples of controlling uplink transmission inaccordance with the DL CC state. In FIGS. 13˜15, it is assumed thatactive/non-active assignment is applied only to the DL CC and notapplied to the UL CC. More specifically, the UL CC may always transmitsignals regardless of the state of the DL CC. Such assumption is justmade in order to explain the present invention, and, therefore,configuring the UL CC to an available/non-available state, as shown inEmbodiment 1 or 2-1, is not excluded. More specifically, the presentinvention may also be applied in cases where the UL CC is configured toan available/non-available state as time goes by.

FIG. 13 shows a case wherein a CQI transmission cycle period isseparately configured for each DL CC, and wherein the CQI for multipleDL CCs is respectively transmitted through multiple UL CCs. In thiscase, depending upon whether or not the DL CC is assigned as anactive/non-active CC, whether or not to transmit the CQI related to thecorresponding DL CC is also decided. Referring to FIG. 13, the time whenthe CQI related to the DL CC#0 is transmitted is configured as subframenumber 1, subframe number 5, subframe number 9, and subframe number 13in UL CC#0. However, DL CC#0 is assigned as a non-active CC in subframenumber 5. Therefore, the CQI related to DL CC#0 is transmitted onlythrough subframe number 1, subframe number 9, and subframe number 13 inUL CC#0, and the CQI is not transmitted through subframe number 5. Inparticular, a user equipment performs a procedure of determiningphysical uplink channel assignment for a transmission of the CQI at asubframe on which the CQI shall be transmitted, in which the CQI isconfigured not to be transmitted when a corresponding UL CC is in astate of non-available UL CC. That is, when the corresponding UL CC in astate of non-available UL CC, the user equipment may not assign aphysical channel to the CQI at the corresponding subframe. In FIG. 13,it is assumed that the CQI for subframe number n in DL CC#0 istransmitted through subframe number n in UL CC#0. However, this ismerely an example given for the description of the present invention.Therefore, an index of a downlink subframe, wherein the downlink channelis actually measured, and an index of an uplink subframe, wherein theCQI is transmitted, may be different from one another. For example, theCQI being transmitted through subframe number 5 of UL DC#0 may berelated to the channel quality of subframe number 3 in DL CC#0 (i.e., adifference of 2 subframes). In this case, whether or not to transmit theCQI through subframe number 5 of UL CC#0 may be decided based uponwhether or not subframe number 3 of DL CC#0 is configured as anon-active state.

FIG. 14 shows a case wherein a CQI transmission cycle period isseparately configured for each DL CC, and wherein the CQI for multipleDL CCs is transmitted through a single UL CC. In this case, dependingupon whether or not the DL CC is assigned as an active/non-active CC,whether or not to transmit the CQI related to the corresponding DL CC isalso decided. A specific UL CC configured so that CQI for multiple DLCCs can be transmitted may be referred to as an anchor or primary UL CC.Referring to FIG. 14, the time when the CQI related to the DL CC#0 istransmitted is configured as subframe number 1, subframe number 5,subframe number 9, and subframe number 13 in UL CC#1. However, DL CC#0is assigned as a non-active CC in subframe number 5. Therefore, the CQIrelated to DL CC#0 is transmitted only through subframe number 1,subframe number 9, and subframe number 13 in UL CC#1, and the CQI is nottransmitted through subframe number 5. Similarly, UL CC#1 may send CQIinformation corresponding to each DL CC depending upon theactive/non-active CC assignment for DL CC#1 and DL CC#2. In UL CC#1,subframe number 9 corresponds to the CQI transmission time of two DL CCs(DL CC#0, DL CC#2). And, at the same time, since both of the twocorresponding DL CCs (DL CC#0, DL CC#2) are assigned as active CCs, theCQI information on both DL CCs (DL CC#0, DL CC#2) are transmittedsimultaneously.

FIG. 15 shows a case wherein the CQI for multiple DL CCs is respectivelytransmitted to multiple UL CCs, yet wherein, considering thetransmission cycle period/offset between the CCs, the overalltransmission is performed by using the TDM method. With the exception oftransmitting the CQI related to each DL CC by using the TDM method, theremaining process is identical to those described in FIG. 13 and FIG.14. Therefore, since reference may be made to FIG. 13 and FIG. 14,detailed description of the same will be omitted for simplicity.

The above-described examples are given to facilitate the understandingof the present invention. Therefore, the present invention may also beapplied to other diverse methods of the CQI transmission method inaddition to the above-described examples. Also, in FIG. 13 to FIG. 15,the DL subframe index and the UL subframe index are used to facilitatethe description of the present invention. Accordingly, identical DL/ULsubframe indexes do not necessarily signify subframes at the same timepoint. In other words, a timing of a predetermined time interval mayexist between the DL subframe and the UL subframe.

Embodiment 2-3 Control of an Uplink Transmission Considering the Stateof the DL CC (2)

This embodiment of the present invention proposes a method oftransmitting CQI to the corresponding UL CC depending upon apredetermined configuration, when the time point corresponding to thetransmission cycle period of the CQI matches with the time point wherethe DL CC is assigned as an active CC, and transmitting CQI by usinganother configuration, when the DL CC is assigned as a non-active CC atthe time corresponding to the transmission cycle period of the CQI. Forexample, when the DL CC is configured as a non-active state, the userequipment may use another configuration (parameter) for the CQI (e.g.,transmission cycle period/pattern/measurement band etc.) differentlyfrom the predetermined configuration.

This embodiment of the present invention may be used along with a CQItransmission stop operation proposed in Embodiment 2-2, or may be usedoptionally. More specifically, when the DL CC is configured as an activeCC, the user equipment may perform CQI transmission in accordance withthe predetermined CQI configuration, and, then, when the correspondingDL CC is configured as a non-active CC, the CQI transmission may bestopped (SRS off), as proposed in Embodiment 2-2, or the CQI may betransmitted in accordance with the modified configuration.

FIG. 16 illustrates an example of controlling uplink transmission of theCQI according to an embodiment of the present invention. According tothe predetermined CQI configuration, it is assumed that the CQI cycleperiod is 2 ms (2 subframes) and that 2 BW parts (BP1˜2) exist within aWB. In this case, the CQI is transmitted for each 2 ms in the order ofWB→BP1→BP2. Referring to FIG. 16, when the DL CC is configured as anon-active CC from an active CC, the CQI may be transmitted inaccordance with the following modified methods. The methods describedbelow are given to facilitate the understanding of the presentinvention, and each method may be used independently or in combination.

Method 1-1: Only the CQI transmission cycle period may be modified fromthe predetermined CQI configuration, so as to perform CQI transmission.For example, when the DL CC is in a non-active state, the CQItransmission cycle period may be changed to an integral multiple of thepredetermined cycle period (e.g., 2 ms×2=4 ms).

Method 1-2: Herein, Method 1-1 may be applied. However, the measurementband of the CQI being transmitted with the modified cycle period may bechanged from the initial (or original) CQI transmission order. Forexample, when the DL CC is non-active, the transmission order of the CQIband may be changed from WB→BP1→BP2 to BP1→WB→BP2.

Method 1-3: The CQI transmission cycle period and measurement band(e.g., WB CQI) may both be modified from the predetermined CQIconfiguration, so as to perform CQI transmission. For example, when theDL CC is non-active, the CQI transmission cycle period is modified to 2ms×3=6 ms, and the CQI measurement band may be modified to WB→WB→WB→BP2.

Method 1-4: Based upon the predetermined CQI configuration, only the CQItransmission cycle period for the same band may be modified (e.g.,integral multiple). For example, when the WB→BP1→BP2 is transmitted, thetransmission cycle period for each CQI is maintained at 2 ms. And, whena CQI is newly transmitted for the same band, the CQI transmission cycleperiod may be modified to an integral multiple of the predetermined CQItransmission cycle period (e.g., 2 ms×4=8 ms). Therefore, in FIG. 16, aCQI transmission time interval between BP2→WB becomes 8 ms.

Signaling for the embodiment of the present invention may be diverselyimplemented. For example, the signaling for the embodiment of thepresent invention may be included in a control signal (e.g., L1/L2control signaling or RRC signaling) for configuring active/non-activeCC, so as to be transmitted. In another example, a control channel(e.g., PDCCH) changing the CQI parameter for non-active DL CC may beseparately configured.

More specifically, in case of CQI off, 1-bit signaling may be performed.And, in case of Method 1-1˜1-4, modified CQI transmission cycleperiod/pattern/measurement band values, which are predetermined fornon-active CCs may be applied based upon the 1-bit signaling, or themodified CQI transmission cycle period/pattern/measurement band valuesmay be directly signaled. Also, a method of selecting/combining the CQIoff and Methods 1-1˜1-4 may also be used in accordance with one field.Also, 2 CQI configurations, which are to be applied to active andnon-active CCs in Methods 1-1˜1-4, may both be predetermined. Forexample, at least one of the transmission cycleperiod/pattern/measurement band may be configured in pairs in a commonsignaling information.

Embodiment 2-4 Control of an Uplink Transmission in Accordance with a ULCC State

An SRS is a signal transmitted from the user equipment to the basestation in order to be informed of the uplink channel state. Therefore,even when the DL CC is assigned as a non-active CC, and even in acondition wherein the user equipment does not receive data via downlink,for the scheduling for an uplink data transmission of the userequipment, the base station should be informed of the uplink channelinformation of each UL CC. Accordingly, whether or not to transmit theSRS may be decided in accordance with the active/non-active state (oractivation/non-activation) of the UL CC that is to be transmitted,regardless of the active/non-active CC assignment of the DL CC. Theactive/non-active state (or activation/non-activation) of the UL CC maybe dynamically or semi-statically modified. For simplicity, the activestate of the UL CC may be referred to as an activated UL CC, and thenon-active state of the UL CC may be referred to as a deactivated UL CC.In the embodiment of the present invention, the deactivated UL CC may bedefined as described in the example shown in Embodiment 1. And, moreparticularly, the deactivated UL CC may be defined as a UL CC configuredto have a limited transmission only for the uplink data channel (e.g.,PUSCH), or as a UL CC configured to have a limited transmission (e.g.,PUCCH) of some control information along with the data transmission.

Therefore, this embodiment of the present invention proposes a method oftransmitting SRS on the corresponding UL CC depending upon apredetermined configuration, when the time point corresponding to thetransmission cycle period of the SRS matches with the time when the ULCC is assigned as an active CC, and transmitting SRS by using anotherconfiguration, when the UL CC is assigned as a non-active CC at the timecorresponding to the transmission cycle period of the SRS. For example,when the UL CC is configured in a non-active state, the user equipmentmay use another configuration (parameter) for the SRS (e.g.,transmission cycle period/pattern/measurement band etc.) differentlyfrom the predetermined configuration.

In the embodiment of the present invention, the method of modifyingactivation/deactivation of the UL CC is not limited. For example, the ULCC may be activated/deactivated separately from the DL CC, or the UL CCmay be activated/deactivated in accordance with the active/non-active CCassignment for the DL CC. Therefore, when the active/non-active state ofthe UL CC is decided by the DL CC linked to the corresponding UL CC, themodification of the parameter for SRS transmission may be applied to theUL CC linked to the non-active DL CC. Conversely, when theactive/non-active state of the UL CC is decided regardless of the DL CC,the modification of the parameter for SRS transmission may be applied tothe non-active UL CC. Furthermore, the transmission cycle period of theSRS may be independently assigned among the UL CCs. And, the cycleperiod among multiple UL CCs may be adjusted in order to performassignment so that transmission can be performed by using the TDMmethod. Additionally, the assignment may be performed by using otherdiverse methods.

The embodiment of the present invention may be used along with the SRStransmission stop operations proposed in Embodiment 2-1, or theembodiment of the present invention may be used optionally. Morespecifically, when the UL CC is configured as an active CC, the userequipment may perform SRS transmission in accordance with thepredetermined SRS configuration. Then, when the corresponding UL CC isconfigured as an inactive CC, as proposed in Embodiment 2-1, the SRStransmission may be stopped (SRS off) or transmission may be performedin accordance with a modified SRS configuration.

FIG. 17 shows an example of controlling an uplink transmission of an SRSaccording to the embodiment of the present invention, According to thepredetermined SRS configuration, an SRS cycle period is 2 ms (2subframes) and 4 SRS BWs (SB1˜4) exist within an SRS hopping BW (WB). Inthis case, the SRS is transmitted at each 2 ms, and frequency hopping isperformed in the order of SB1→SB3→SB2→SB4.

Referring to FIG. 17, when the UL CC is configured as a non-active CCfrom an active CC, the SRS may be transmitted in accordance with thefollowing modified methods. The methods described below are given tofacilitate the understanding of the present invention, and each methodmay be used independently or in combination.

Method 2-1: Only the SRS transmission cycle period may be modified fromthe predetermined SRS configuration, so as to perform SRS transmission.For example, when the UL CC is in a non-active state, the SRStransmission cycle period may be changed to an integral multiple of thepredetermined cycle period (e.g., 2 ms×3=6 ms).

Method 2-2: Herein, Method 2-1 may be applied. However, the transmissionband of the SRS being transmitted with the modified cycle period may bechanged from the initial (or original) SRS transmission order. Forexample, when the UL CC is non-active, the transmission order of the SRSband may be changed from SB1→SB3→SB2→SB4 to SB2→SB3→SB1→SB4.

Method 2-3: The SRS transmission cycle period and transmission band mayboth be modified from the predetermined SRS configuration, so as toperform SRS transmission. In this case, when the UL CC is in anon-active state, the SRS BW may be configured to be equal to or largerthan the SRS hopping BW. When the UL CC is non-active, the SRStransmission cycle period is modified to 2 ms×4=8 ms, and the SRStransmission band may be modified to WB.

Method 2-4: Based upon the predetermined SRS configuration, only the SRStransmission cycle period for the same band may be modified (e.g.,integral multiple). For example, when 4 SRS BWs within the SRS hoppingBW are transmitted, the SRS transmission cycle period is maintained at 2ms. And, when an SRS is newly transmitted for the same band, the SRStransmission cycle period may be modified to an integral multiple of thepredetermined SRS transmission cycle period (e.g., 2 ms×5=10 ms).Therefore, in FIG. 17, an SRS transmission time interval between SB4→SB1becomes 10 ms.

Signaling for the embodiment of the present invention may be diverselyimplemented in accordance with the active/non-active UL CC configurationmethod. For example, when the UL CC is activated/deactivated by theactive/non-active CC assignment of the DL CC, the signaling for theembodiment of the present invention may be performed through a controlsignal (e.g., L1/L2 control signaling or RRC signaling) for configuringactive/non-active DL CC. In another example, when the UL CC isactivated/deactivated regardless of the DL CC, the signaling for theembodiment of the present invention may be performed through a controlsignal (e.g., L1/L2 control signaling or RRC signaling) for configuringactive/non-active UL CC. In yet another example, a control channel(e.g., PDCCH) changing the SRS parameter for non-active UL CC may beseparately configured.

More specifically, in case of SRS off, 1-bit signaling may be performed.And, in case of Method 2-1˜2-4, modified SRS transmission cycleperiod/pattern/transmission band values, which are predetermined fornon-active UL CCs may be applied based upon the 1-bit signaling, or themodified SRS transmission cycle period/pattern/transmission band valuesmay be directly signaled. Also, a method of selecting/combining the SRSoff and Methods 2-1˜2-4 may also be used in accordance with one field.Also, 2 SRS configurations, which are to be applied to active andnon-active UL CCs in Methods 2-1˜2-4, may both be predetermined. Forexample, at least one of the transmission cycleperiod/pattern/transmission band may be configured in pairs in a commonsignaling information.

FIG. 18 illustrates exemplary base station and user equipment that canbe applied to the embodiment of the present invention.

Referring to FIG. 18, a wireless communication system includes a basestation (BS) (110) and a user equipment (UE) (or terminal) (120). In adownlink, a transmitter corresponds to a portion of the base station(110), and a receiver corresponds to a portion of the UE (120). In anuplink, a transmitter corresponds to a portion of the UE (120), and areceiver corresponds to a portion of the base station (110). The basestation (110) includes a processor (112), a memory (114), and a radiofrequency (RF) unit (116). The processor (112) may be configured toembody the procedures and/or methods proposed in the present invention.The memory (114) is connected to the processor (112) and stores diverseinformation associated with the operation of the processor (112). The RFunit (116) is connected to the processor (112) and transmits and/orreceives a radio signal. The UE (or terminal) (120) includes a processor(122), a memory (124), and an RF unit (126). The processor (122) may beconfigured to embody the procedures and/or methods proposed in thepresent invention. The memory (124) is connected to the processor (122)and stores diverse information associated with the operation of theprocessor (122). The RF unit (126) is connected to the processor (122)and transmits and/or receives a radio signal. The base station (110)and/or the UE (120) may have a single antenna or multiple antennae.

The aforementioned embodiments are achieved by combination of structuralelements and features of the present invention in a predetermined type.Each of the structural elements or features should be consideredselectively unless specified separately. Each of the structural elementsor features may be carried out without being combined with otherstructural elements or features. Also, some structural elements and/orfeatures may be combined with one another to constitute the embodimentsof the present invention. The order of operations described in theembodiments of the present invention may be changed. Some structuralelements or features of one embodiment may be included in anotherembodiment, or may be replaced with corresponding structural elements orfeatures of another embodiment. Moreover, it will be apparent that someclaims referring to specific claims may be combined with another claimsreferring to the other claims other than the specific claims toconstitute the embodiment or add new claims by means of amendment afterthe application is filed.

The embodiments of the present invention have been described based onthe data transmission and reception between the base station and theuser equipment. A specific operation which has been described as beingperformed by the base station may be performed by an upper node of thebase station as the case may be. In other words, it will be apparentthat various operations performed for communication with the userequipment in the network which includes a plurality of network nodesalong with the base station can be performed by the base station ornetwork nodes other than the base station. The base station may bereplaced with terms such as a fixed station, Node B, eNode B (eNB), andaccess point. Also, the user equipment may be replaced with terms suchas mobile station (MS) and mobile subscriber station (MSS).

The embodiments according to the present invention can be implemented byvarious means, for example, hardware, firmware, software, or theircombination. If the embodiment according to the present invention isimplemented by hardware, the embodiment of the present invention can beimplemented by one or more application specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), processors, controllers, microcontrollers,microprocessors, etc.

If the embodiment according to the present invention is implemented byfirmware or software, the embodiment of the present invention may beimplemented by a type of a module, a procedure, or a function, whichperforms functions or operations described as above. A software code maybe stored in a memory unit and then may be driven by a processor. Thememory unit may be located inside or outside the processor to transmitand receive data to and from the processor through various means whichare well known.

It will be apparent to those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit and essential characteristics of the invention. Thus, theabove embodiments are to be considered in all respects as illustrativeand not restrictive. The scope of the invention should be determined byreasonable interpretation of the appended claims and all change whichcomes within the equivalent scope of the invention are included in thescope of the invention.

INDUSTRIAL APPLICABILITY

The present invention may be applied to a wireless communication system.More specifically, the present invention may be applied to acommunication method using a carrier aggregation and apparatustherefore.

1. A method of controlling uplink transmission at a user equipment in awireless communications system, wherein the user equipment is configuredwith multiple component carriers, the method comprises: receivingconfiguration information for transmitting an uplink signal from a basestation, the configuration information including information forperiodically transmitting the uplink signal to the base station; andperforming operations for periodically transmitting the uplink signal tothe base station on a corresponding uplink component carrier in use ofthe configuration information, wherein if the corresponding uplinkcomponent carrier is in an available state at a time for transmittingthe uplink signal, the uplink signal is transmitted on the correspondinguplink component carrier at the time, wherein if the correspondinguplink component carrier is in a non-available state at a time fortransmitting the uplink signal, the uplink signal is not transmitted onthe corresponding uplink component carrier at the time.
 2. The method ofclaim 1, wherein the configuration information is received using a RadioResource Control (RRC) signal.
 3. The method of claim 1, wherein theuplink signal includes at least one of a CQI (Channel QualityIndicator), a PMI (Precoding Matrix Indication), an RI (RankInformation), and an SRS (Sounding Reference Signal).
 4. The method ofclaim 1, wherein whether or not the corresponding uplink componentcarrier is in a non-available state is identified by using a state of adownlink component carrier linked to the corresponding uplink componentcarrier.
 5. The method of claim 4, wherein the corresponding uplinkcomponent carrier is configured as a non-available state, when multipledownlink component carriers linked to the corresponding uplink componentcarrier are all in a non-available state.
 6. The method of claim 1,wherein whether or not the corresponding uplink component carrier is ina non-available state is identified by using L1/L2 control signaling. 7.A user equipment configured to communicate with a base station usingmultiple component carriers in a wireless communications system, theuser equipment comprising: a radio frequency (RF) unit configured totransmit and receive wireless signals to and from the base station; amemory configured to store information being transmitted and received toand from the base station and parameters required for performingoperations of the user equipment; and a processor configured to beconnected to the RF unit and the memory, and configured to control theRF unit and the memory, so as to operate the user equipment, wherein theprocessor is configured to receive configuration information fortransmitting an uplink signal to the base station, the configurationinformation including information for periodically transmitting theuplink signal to the base station, and to perform operations forperiodically transmitting the uplink signal to the base station on acorresponding uplink component carrier in use of the configurationinformation, wherein if the corresponding uplink component carrier is inan available state at a time for transmitting the uplink signal, theuplink signal is transmitted on the corresponding uplink componentcarrier at the time, wherein if the corresponding uplink componentcarrier is in a non-available state at a time for transmitting theuplink signal, the uplink signal is not transmitted on the correspondinguplink component carrier at the time.
 8. The user equipment of claim 7,wherein the configuration information is received using a Radio ResourceControl (RRC) signal.
 9. The user equipment of claim 7, wherein theuplink signal includes at least one of a CQI (Channel QualityIndicator), a PMI (Precoding Matrix Indication), an RI (RankInformation), and an SRS (Sounding Reference Signal).
 10. The userequipment of claim 7, wherein whether or not the corresponding uplinkcomponent carrier is in a non-available state is identified by using astate of a downlink component carrier linked to the corresponding uplinkcomponent carrier.
 11. The user equipment of claim 10, wherein thecorresponding uplink component carrier is configures as a non-availablestate, when multiple downlink component carriers linked to thecorresponding uplink component carrier are all in a non-available state.12. The user equipment of claim 7, wherein whether or not thecorresponding uplink component carrier is in a non-available state isidentified by using L1/L2 control signaling. 13-14. (canceled)